Saturday, April 05, 2008

Science of foam, beer, bubbles and soap suds

The Physics of Foams by Denis Weaire and Stefan Hutzler
Coherent and succinct introduction to foamy physics

The Physics of Foams by Denis Weaire and Stefan Hutzler is a lucid, terse and coherent introduction to the realm of foams. Weaire, who is co-author of another delightful text "The Pursuit of Perfect Packing", presents ideas about minimum surfaces, packing problems, and associated structural question with simple and elegant examples.

The authors use minimum of mathematics to emphasize the key ideas related to foam rheology, drainage, stability, structure, coarsening and conductivity. By drawing their examples from varied sources (bubble rafts, beer foam, metal foam, magnetic froth, soap suds), and citing relevant experimental and simulation results that explain the concepts, Weaire and Hutzler have created a text that will be handy to instructors everywhere. As a scientific treatise, it connects our understanding with ideas emanating from observing beer and soap bubbles, thinking about Kepler or Kelvin's hypothesis about packing, and basic understanding of properties of (complex) fluids. The text is entertaining, and is supplemented by innumerable illustrations to make it a worthwhile reading for anyone remotely interested in foam physics.

In context of the other review, I may add that the text comes with a list of useful articles and books that can be referred to by the serious researchers interested in deeper questions or details left out of the text. Brevity of presentation has its own merits, and learning and teaching through analogies and intuition is favored and practiced in this informal, but elegant text. Recommended reading!

Universal Foam by Sidney Perkowitz
An entertaining and illuminating journey into foam physics

In Universal Foam by Sidney Perkowitz, we encounter everyday phenomenon and objects - coffee froth, beer head, styrofoam cups, soap suds, shaving cream, bread, cork - and begin to see the underlying mystery, pleasure and physics, that guides their appearance, form and function. The science of bubbles contains answers to complex and varied questions: puzzles about the origin of universe and the softness of bread are revealed and deciphered using foam physics. As a teacher, Perkowitz exudes a ready wit, an imitable enthusiasm about the subject.

After reading this book, the ubiquitous foaminess of the world will reveal itself to you at every juncture. A glass of beer will turn into a laboratory for experiments about size dependence of bubbles of the froth, their stability and strength, and their variation with brand. As you stir your coffee, the foam will organize into patterns; corks on wine bottle will spark discussions about why certain champagnes taste better just because of their packaging. A walk by seaside or river will prompt observations about how much rain (and condensation nuclei) is being generated by the white effervescent milkiness that rides the waves. Night sky shall beckon your thoughts about big bang and about questions as philosophical as "do we really live in a bubble?" The book will reveal the scientific merit of such a question (and many more).

Universal foam is a great read, both as an introduction to the initiated, and as a witty jaunt for they who work their hours of intellectual activity by exploding or imploding bubbles. If you are looking for a more mathematical account, "The Physics of Foams" by Denis Wearie and Stefan Hutzler will provide you both with entertainment and equations in a beery Irish manner. (The text starts with the line: "Pour a bottle of beer")

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